1. Field of the Invention
The present invention relates to digital televisions, and more particularly, to a multi-source image format converter that receives various types of input images and converts their formats and sizes in order to adequately display them on a display device according to a display mode.
2. Background of the Related Art
As a result of a recent introduction of digital televisions, various new television systems are currently being introduced. For example, some of them are built-in type digital television sets that decode and display compressed digital image data, a set-top box (STB) that only contains a decoding function, and digital ready television sets for receiving output signals from STB or analog image signals. These digital systems receive various input image signals such as high definition level (HD) and standard level (SD) image signals, computer or video image signals, and analog signals. When such various input image signals are inputted to a display device, the output image also needs to have various formats. For that reason, a multi-source format converter is necessary.
Among the digital television sets mentioned earlier, especially the digital ready television sets are presumed to be widely used in the future due to several advantages they have. They are considered as analog television sets with extended capabilities or new types of TV sets. The conventional analog TV sets perform a simple function such as receiving input images having a limited format and generating output images having a similar format. Therefore, they did not necessitate an additional multi-source format converter or image-processing device. For example, even expensive analog TV sets converts and displays various input images using a simple format converter having limited capabilities. On the other hand, the digital TV sets must receive input images having various formats such as analog NTSC images, personal computer images (VGA, XGA), 480P, 720P, and 1080I (interlaced) formats. Also, various display functions must be provided for digital ready TV sets such as PIP (picture-in-picture), multi-PIP, POP (picture-outside-picture), split-screen, freeze, zoom-in, zoom-out, and graphics. More importantly, they must provide an outstanding image quality as well as the special functions and capabilities mentioned earlier.
However, the conventional format converter is not suitable for performing complicate functions in digital TV sets such as the digital ready TV sets. In other words, it is impossible to convert various input images to output images having various formats using the conventional format converter. Its limited expandability also results conflicts when additional input image data need to be displayed as well as prior input image.